Senior Frontend Developer

Empat is a founder-led software engineering company with 11+ years on the market, 300+ delivered projects and a team of 150+ professionals across offices in Kyiv, London and San Francisco.

We build digital products for scaling startups and established enterprises across North America, Europe and the UK, with particular strength in Healthcare, FinTech, E-commerce and Avionics. We operate as an AI-native engineering company, and our culture is built on empathy - toward clients, end users, partners and each other.

Empat is a four-time Clutch Top 100 Fastest Growing honoree (2023-2026) with a 5.0 rating across 150+ client reviews.

What the role looks like:

We’re looking for a Senior Frontend Engineer to join a UK-based startup full-time and work on one product. The product is a supply-chain intelligence platform for the chemicals industry. It models cost and carbon footprint across real supply chains, and large enterprise companies already use it in production. It’s a multi-tenant analytics platform with an AI agent that renders real UI, not only text. The product grows fast and priorities change often. You’ll work directly with the whole UK team, including the CTO and CEO, and over time take ownership of the frontend direction: architecture, standards and code review. Full-stack engineers are welcome when frontend is clearly their main strength.

Stack: Next.js 16 App Router, React 19 with React Compiler, TypeScript 6, MUI v9, TanStack Query 5, Zustand 5, React Hook Form + Yup, recharts, CopilotKit, Mapbox GL, Vitest + RTL, Playwright, Storybook. Backend: Python and FastAPI.

Your responsibilities will include:

• Owning features end to end: API integration, state, UI, tests, accessibility and performance;
• Building data-heavy interfaces: tables, filters, charts and maps;
• Building UI that an AI agent renders from a schema, and handling incomplete or malformed model output;
• Turning vague requests into testable requirements, and writing the spec yourself when there is none;
• Delivering through agentic coding tools, behind a heavily automated quality gate;
• Raising problems early and proposing how to fix them.

What we expect from you:

• 5+ years of commercial frontend experience, at least 3 of them building React products in TypeScript;
• Shipped a Next.js App Router application and decided what renders on the server and what ships to the browser;
• Strict TypeScript: generics, unions, narrowing, schema-inferred types;
• Daily, deep use of an agentic coding tool (Claude Code, Cursor agents, Codex or equivalent). You delegate whole tasks, run sub-agents and wire MCP tools. Autocomplete-level use is not enough;
• You verify AI output before shipping and turn repeated mistakes into lint rules, checks or tests;
• Proper use of a server-state library (TanStack Query, React Query or SWR);
• A client-state store (Zustand, Redux or MobX);
• Forms with schema-driven validation, including server errors mapped onto fields;
• A themed component library with design tokens (MUI, Chakra, Mantine or similar);
• Charts with a real charting library (recharts, visx, ECharts or D3);
• Component and hook tests as part of your own work;
• Fluent English: C1 preferred, strong B2+ (Upper-Intermediate) considered. You’ll speak and write in English with the team every day;
• Proactive, independent and direct. You drive the work rather than wait for detailed tasks, and you raise blockers early;
• Curious about the domain. You want to understand why the business needs a feature, not only how to build it.

We don’t require the exact libraries above. A close equivalent is fine for state management, forms, component libraries, charts and testing.

Nice to have:

• Generative UI or LLM tool-calling on the frontend (CopilotKit, AG-UI, Vercel AI SDK);
• Mapbox GL or other heavy data-visualisation work;
• Design systems in Storybook, visual-regression pipelines;
• A spec-first or test-first process in a previous team;
• Python and FastAPI;
• i18n, Sentry, PostHog, WorkOS, Auth0 or Clerk.

What We Offer:

• Work in Top-employee company (according to DOU 2025);
• Paid time off, including vacation and sick days;
• Interesting projects and challenges that will ensure your development as a specialist and as a person;
• Work in a team of creative, proactive and empathic people;
• A comfortable, stylish and sunny office with a view of the city center (Chykalenka str) and the opportunity to work from home (office equipped with generator and battery installation);
• Lack of bureaucracy, regular feedback and support from colleagues;
• Fun parties, online activities, picnics and more.